This invention relates to load elevators of the collapsible type, a common example of which is a truck tailgate lift.
For some types of freight a load lifting and lowering platform of large area, e.g., 6 .times. 6 feet, is required by trucks for tailgate mounting. For such use there is a species of lift whose supporting framework includes a pair of laterally spaced apart channels framing the sides of the truck's tailgate opening to vertically movably mount a pair of lifting legs on or in the guide channels. The lifting legs pivotally carry a forward platform section that, in turn, hingedly carries an outer platform section. Erlinder U.S. Pat. No. 3,831,788 discloses a lift of this type which is only partially self-folding in response to actuation of the power means for the lift, in that it employs two pairs of chains, one set of which must be detached in an intermediate step of folding or unfolding the lift. Martin U.S. Pat. No. 3,795,329 discloses another lift of this class which is manually movable for folding and unfolding, which is a very great disadvantage considering the weight of the platform sections. The prior art devices are comparatively complex and have several other operational disadvantages.